Mark (√) against the correct answer in the following:
Question:

Mark (√) against the correct answer in the following:

Let $f(x)=\sqrt{\cos x}$. Then, dom $(f)=?$

A. $\left[0, \frac{\pi}{2}\right]$

B. $\left[\frac{3 \pi}{2}, 2 \pi\right]$

C. $\left[0, \frac{\pi}{2}\right] \cup\left[\frac{3 \pi}{2}, 2 \pi\right]$

D. none of these

Solution:

$f(x)=\sqrt{\cos x}$

As per the diagram

We can imply that domain of $\sqrt{\cos x}$

is $\left[0, \frac{\pi}{2}\right]\left[\frac{3 \pi}{2}, 2 \pi\right]$